I have a 1983 E350, 351W, edelbrock 4barrel carb and manifold, AT, power assist brakes, power steering, no A/C, no power windows, etc.

this vehicle was purchased 2 years ago and was a former school district service vehicle. supposedly rebuilt at some point.

I use the van for mostly personal use but serve as an FedEx driver when needed (outside cartage agent)

(friday)
the van recently started dying on me on deceleration when at operating temps. at first it was pretty random but got more frequent. now I cannot get down the road more than a mile or so. (with one exception).

(saturday)
I started by doing a tune up. plugs, wires, cap rotor. then moved to vacuum lines. (monday) then ignition module. followed by (tuesday) vacuum modulator on transmission. this seemed to work for a bit, (it had fluid up in the vacuum line) but in the end was not the issue.

(wednesday)
I went to get gas and go next door to the parts house to get a distributor wrench. the van died three times getting next door (literally 300 feet) purchased a coil instead and drove to Medford 30 miles away and back with no issues (the exception). then the alternator light came on. I changed alternator and regulator (external)

(friday)
today at a recommendation I changed out the ignition switch.

all to no avail. I can get it started put it in gear and give a little goose taking off from a start and let off the throttle and it will die.

it only does this when I let off throttle as when coming to a stop or turning into a drive or street after it has reached operating temps. (never has gone above a needles width above the lowest line)

I covered primaries on carb and it chokes out, so I assume the vacuum is good (all new lines). all electrical has now been replaced. have swapped coils a couple times, and assume the ignition module may have been good (still have it) and it appears the ignition switch may not have been the culprit either.....

the idle screws on the carb were about 2 1/4 turns out they are now about 2 turns. readjusted the timing.

the power booster and master cylinder were replaced 1 1/2 years ago along with pads and the starter. the rear cylinders and shoes were replaced two weeks ago. this is the only work I have done on the van in two years

I am at a loss and so is everyone I have talked with. any hints, clues, or whacks upside the head?

thank you for your time and responses

Jon

 

Been a long time since I've messed with a carb, but sounds fuel related to me. Have you changed out your fuel filter? Mechanical or electric fuel pump? Beyond just the jets, have you tried doing a full tuneup/adjustment to the carb?

Anyway, I'd pay more mind to the fuel system and less to electrical at this point.

 

it is getting good fuel flow to the carb and the issue only happens when warm.

mechanical pump and two fuel filters I'll change them tomorrow (the filters)

on the upside when this is done I wont have to work on it for another two years

 

at this point its carb or distributor pickups....I think/hope

 

changed the fuel filters no difference, buy fuel flow was intermediate and low at best (got clear filters to check fuel flow). so changed fuel pump (oil was coming out the weep hole). no difference. took out fuel sender and checked filter on pickup and it seemed ok.

took the top off the carb and there was some algae looking brown crap in it so flushed it and wiped it out. is running much better, but now needs some adjusting and retiming ( has a rough idle) and it did die once on the last test run but without carb rebuild I suspect that would happen

so rebuild the carb and hopefully all my problems (and then some) will be resolved

on the plus side the trans vacuum modulator was bad and it looks like the fuel pump was on its way out (both filters are running full now)

new ignition module and coil and discovered bad bearings in the alternator.

spent more time and money than I would have liked but I should be trouble free for a bit

 

Have you scan van for codes?
Even if your check engine light is off, you still may have some codes store in memory.

The symptoms in your van could be related to TFI( control module) but I could be wrong.

I am am not sure if your TFI is located on fender or distributor but in either case the same rule applies.

If you replaced TFI make sure you installed the correct one.There is two types of TFI installed on vans and even though they look alike and they fit .However,they are not interchangeable.More important, I would advice to use a motorcraft one.They are not cheap but you can shop around or do what I did.I was short in cash and I used one from the junk yard and it worked great.

Color grey TFI uses a 22k ohms resistor which is usually a attached to wire number 4(IDM)close to the TFI wiring harness. Dont count on the autopart stores to tell you which one do you have because they dont have a clue and neither does the dealers.

Color Black TFI does not use the resistor and relies on the computer to operate. However, there is a 10 uf capacitor inside computer that if it goes bad it will give you all kind of problems related to ignition.

Before you go crazy replacing parts, I would advice you to check inside the computer and look at the capacitors.There are 3 inside and thery are blue in color and only 1 is rated 10uf. Look for a brownish color wich is and indication that it is burn out. Sometimes if it is only slightly damage look at the bottom of it and look for a sign of tar looking stuff that is is also and indication that it is out or just just about.

Removing the computer is very simple and while at it clean that wire harnesses with electronic cleaner and use dielectric grease when you put it back.

I may be wrong with the capacitor thing but it is worth a shot. I did it and it pay off big deal on my 94 E350, 351 windsor engine.